This research contributes to answer the question whether learning/cognitive styles of students serve as a justified starting point for creating target-group appropriate instruction. The study was realized in a self-regulated problem-based learning environment. Data of 56 participants on their individual learning styles, their acquired problem solution and their increase in declarative knowledge were collected. Results indicate that a consideration of learning styles to design a matching instruction or learning environment does not transfer into higher quality problem solutions or an enhanced increase in declarative knowledge. (Contains 1 table.) [For the complete proceedings, "Proceedings of the International Association for Development of the Information Society (IADIS) International Conference on Cognition and Exploratory Learning in Digital Age (CELDA) (Madrid, Spain, October 19-21, 2012)," see ED542606.]